Vibratory compacting machines



June 4, 1968 s. W LS 3,385,353

VIBRATORY COMPACTING MACHINES 2 Sheets-Sheet 1 Filed April 6, 1966 June 4, 1968 5. s. WELLS f ,3

VIBRATORY COMPACTING MACHINES I 2 Sheets-Sheet 2 Filed April 6, 1966 United States Patent 3,386,353 VIBRATORY COMPACTING MACHINES Gorden S. Wells, Binghamton, N.Y., assignor to Stow Manufacturing Co., Binghamton, N.Y., a corporation of New York Filed Apr. 6, 1966, Ser. No. 540,591 13 Claims. (Cl. 94-48) ABSTRACT OF THE DISCLOSURE The present disclosure is generally directed to the control of tamper engine speed and, more particularly, to means for setting the speed of a tamper engine so that the latter can :be run only at an idling speed or an operating speed determined at the factory to be a safe operating speed, i.e. one that will not result in impairment or destruction of the tamper or parts thereof or of the engine due to excessive vibrations. Such is effected by means of a manually controlled, two-position toggle-actuated means associated with the engine carburetor which in one overcenter position establishes an angular position of the throttle butterfly shaft as results in idling speed and in the other over-center position results in proper operating speed.

In another of its aspects the disclosure relates to enginespeed verifying means operated from the conventional engine governor and which provides a means for determining any deviation in actual engine speed, i.e. either idlingor proper operating speed but particularly the lat ter, from the idling and operating speeds established as in the foregoing.

This invention relates generally to improvements in vibratory compacting machines for use in compacting soil, aggregates, etc. of the type commonly known as tampers, and it is more particularly addressed to means for regulating and thereupon verifying the speed of the engine which drives the vibratory mechanism of such a machine.

As conducive to a proper understanding of the engine speed regulating and verifying means of the invention, it is explained that because the engines of vibratory compacting machines are required to be run at high speeds (of the order of 3,000 r.p.m.), vibrations of considerable amplitude are an inherent characteristic of such machines. In an effort to overcome carburetor breakage and to reduce damage and/ or wear to other tamper parts resulting from this inherent vibration, it was earlier decided to replace the rather heavy carburetor and air cleaner assembly commonly supplied with the engine with a much lighter carburetor and air cleaner assembly.

However, carburetor throttle operation continued to be under the control of a governor mechanism responding to r.p.m. of the engine crankshaft. With this type of control, various high speed settings of the governor could be selected at will by means of a variable speed governor control lever.

As used on vibratory tampers, governor control of throttle has two definite disadvantages. First, the vibrating weight of the linkage between the governor lever and the carburetor throttle lever, together with that of the throttle butterfly shaft, causes great wear at the throttle butterfly, butterfly shaft and shaft bearing surfaces. This wear imposes an objectionable limit to the useful life of the carburetor.

"ice

The second disadvantage results from the fact that the operator in the field is permitted to indiscriminately select the speed at which the engine of the tamper under his control will operate. The danger of this stems from an other of the inherent characteristics of the vibratory tamper, In explanation, tampers have a narrow resonant frequency band in which vibrations will become very violent when the machine is permitted to operate in this area for even a very short period of time. These violent vibrations not only can result in improper tamping due to machine floundering, but also in damage or breakage of various machine parts, notably the rubber handle mounts and the engine mounting bosses and/or bolts, to a degree that the machine may be said to become self-destructive.

Moreover, should the tamper be so constituted that its resonant band is slightly above the point at which the drive clutch between engine shaft and vibratory mechanism engages, it was possible for the operator quite innocently to set the variable speed governor control lever to produce the speed at which resonance occurs, in which case the operator actually contributes to the failure if not destruction of the machine.

With the above in mind, a major object of the invention was to devise means effective to eliminate the possibility of a carburetor of a gas engine, particularly one serving as the prime mover of a vibratory-type tamper, being set to produce the undesirable engine speed or speeds causing excessive vibrations to be produced as aforesaid.

A further object of the invention was the provision of an engine-speed regulating means operating through the engine carburetor, which is so constructed and arranged as to permit only two engine-speed settings, i.e. a setting for the conventional idling speed and a setting for the factory-determined high speed at which a vibratory machine powered by the engine performs with maximum eificiency and without excessive vibration.

Another object of the invention was to further improve engine-speed regulation as aforesaid by the incorporation in the engine of visual speed verification means operated by a governor mechanism and in which the governor acts solely in this capacity, in contrast to its being used as heretofore to regulate engine speed.

Still another object of the invention was to provide for simple yet effective modification of the standard carburetor-air cleaner assembly of the type used on vibratory tamper engines, to the end that the carburetor will cause the engine to run at only two speeds, i.e. an idling speed and a high speed of the order of that enabling the tamper to perform at maximum efliciency and without excessive vibration, and coupled therewith to provide for modification of the conventional speed-setting governor so that, instead of effecting carburetor throttle regulation as is customary, it serves solely as a means for enabling visual indication of the actual speed at which the tamper engine is running when its setting is for high speed, as enables the tamper operator in the field to determine if his tamper is running on speed.

The above and other objects and features of advantage of the invention will be apparent from the following more detailed description thereof, in which reference is had t the accompanying illustrative drawings, wherein FIG. 1 is a side elevation of a tamper-type vibrating machine to which said invention is applied, as seen mately engine level;

FIG. 2 is a partial perspective view looking forwardly on to a portion of the engine crankcase and belt guard housing of the machine illustrated in FIG. 1, the View depicting the herein proposed modification of the governor lever which was formerly linked to the carburetor, as enables it to function as an engine speed indicator;

FIG. 3 is an enlarged side elevation of the engine carburetor shown in FIG. 1, and further illustrating the toggle mechanism associated with its throttle butterfly shaft which effects modification of the carburetor action according to the invention, i.e. so that it will produce only two engine speeds, namely idling speed and proper high speed for maximum tamping efficiency but Without excessive vibrations;

FIG. 4 is a top plan view of the engine carburetor and its action-modifying toggle mechanism shown in FIG. 3; and

FIG. 5 is a half-bottom view of the carburetor and associated action-modifying toggle mechanism.

Referring to the drawings in detail, FIG. 1 illustrates a vibrating machine of the so-called tamper type to which the present invention is applied. Such a machine comprises a float plate having rectangular configuration when viewed in plan, on which is fixedly mounted, by front and rear lug and bolt means generally designated 12a, 12b, a housing 14 containing the vibrating mechanism (not shown), said housing in turn fixedly mounting thereon, as by bolts and bosses generally designated 18a, 18b, an engine 20, usually a gas engine, which drive said vibrating mechanism by belt means (not shown) enclosed within a belt guard housing 22 best seen in FIG. 2.

Secured to the rear face of the engine cover is a carburetor-air cleaner assembly, of which the carburetor 26 is directly albeit through gaskets 26g (FIG. 4) affixed to the rear face of the engine cover and the air cleaner 28 is affixed to the rear side of said carburetor. Also afiixed to the rear face of the engine cover is an exhaust muffler 30 which is arranged at an angle to the front-rear line of the machine so as to direct the exhaust gases therefrom to the side of the machine operator.

Although forming no part of the present invention, it will be seen that said vibrating machine (tamper) is equipped with a pair of wheels 32 disposed generally rearwardly of the float plate 10 and with an upwardlyrearwardly inclined handle 34, to the upper end of which and forwardly of the handle bar 34a is mounted a gas tank 36 connected to the carburetor by a fuel line 38. As with all tampers of the general type illustrated, the wheels 32 are capable of exercising tamper-supporting functlon only when the tamper is tilted in rearward direction by an amount which raises the under face of the float plate 10 from the ground. When so tilted, the tamper may be wheeled to and from the location in which it is to be put into operation. To place the tamper in operation, it is tilted forwardly by the small angle required to lower the under working surface of the tamper or float plate 10 against the ground, as also results in the wheels 32 being lifted from the ground, whereupon the engine 20 is adjusted to run at high speed, such assuming that it Was previously started and was running at idling speed. Thereupon, due to the action of the vibratory mechanism contained within the housing 14, the float or tamper plate 10 delivers a succession of impacting forces to the surface of the material upon which said float plate rests, such as a surface requiring compaction. Also, by virtue of the forward tilt of the machine as a whole When placed in operation and the favoring action of the vibratory mechanism contained within the housing 14, the tamper walks or moves forwardly of its own accord, so to speak, over the ground or other material to be compacted at a speed which varies in accordance with the degree of tilt of the tamper, the operator, generally speaking, being required only to guide the machine in its forward movement.

In all vibratory-type tampers of the prior art of which I am aware, engine speed regulation was effected either by means of a governor mechanism supplied with the engine and which acted on the engine carburetor throttle through linkage extending from the governor lever to said throttle, or manually as by a manually operable throttle level usually also connected to said governor lever. Such an arrangement permitted various high speed settings of the carburetor butterfly to be selected at will simply by shifting the angular position of the governor lever about its turning axis. As explained in the foregoing, this type of speed regulation has two major disadvantages. Pirst, consequent to the vibration inherent in all vibrating-type tampers while in operation, the vibrating weight of the linkage extending between the governor lever and the carburetor throttle lever, plus that of the throttle butterfly shaft, causes substantial Wear at the throttle butterfly, butterfly shaft and shaft bearing surfaces to a degree limiting the useful life of the carburetor. The second disadvantage results from the fact that since governor settings may be selected at will, it was entirely pos sible for an operator in the field to set the governor, and thereby the carburetor throttle, to produce engine speeds which render the machine self-destructive to a degree.

According to the invention, these disadvantages inherent in prior tamper engine speed regulating means are overcome in large measure by providing, in the first instance, engine speed regulating means by which only two engine Speed settings are possible, i.e. an idling speed at which the engine may run during warming up periods and/ or while the tamper is being wheeled short distances between locations at the same job site with the engine running, and a high-speed setting determined at the factory to be the speed at which the tamper operates most effectively and without excessive vibration.

More particularly, and here referring to FIGS. 3-5, said means comprises a toggle lever assembly 40 pivotally mounted for relative arcuate motion in opposite directions on the one extending end of the throttle butterfly shaft 42 of the aforesaid engine carburetor 26 to which is rigidly aflixed the conventional throttle shaft lever 44. As best seen in FIG. 4, said toggle lever assembly 40 comprises a relatively long toggle arm 40a having a bearing 4% afiixed to its shaft-mounting end and being provided at its opposite or free end with a right-angularly bent finger =lug 400. FIG. 4 also shows that the toggle lever assembly 40 is mounted on the throttle butterfly shaft 42 inwardly of said throttl shaft lever 44.

Illustratively, said toggle lever assembly 40 is linked to said throttle shaft lever by a torsion-type toggle spring 46. Thus, assuming that the toggle lever assembly and the throttle shaft lever are in their respective full-line positions in which they are shown in FIG. 3, counterclockwise motion of said toggle lever assembly 40 imparted thereto by direct application of finger pressure of the operator on finger lug 400 results in a toggling operation, i.e. in the spring 46 causing the throttle shaft lever 44 to move overcenter with respect to said toggle lever arm 40a, as in turn results in the throttle butterfly shaft 42 being actuated in clockwise direction through a limited arc. While a flexible pull wire designated 48 adapted to be controlled by the operator is shown to be connected to the finger lug 40c, it is explained that such is used only to return the throttle lever assembly 40 to its full-line or idling position.

The force of the toggle spring 46 reacting against the throttle shaft lever in moving to its over-center position causes the toggle lever assembly 40 to continue its counterclockwise motion until stopped by engagement of the throttle arm 4th: against a stop 50, which latter, as is best shown in FIG. 5, illustrative-1y comprises a finger aflixed at one end by a screw 50a to the bottom of the carburetor bowl or housing in position to extend outwardly therefrom and into the path of motion of said finger lug 40c. Upon the throttle arm 40w making engagement with the stop finger 50, the toggle spring 46 functions both positively to hold the toggle lever assembly in its stop position against the ing 50 and to maintain bias in clockwise direction on the throttle butterfly shaft 42.

According to a further feature of the invention, clockwise motion of the throttle shaft 42 under the kick of the toggle spring 46 acting through said throttle shaft lever as aforesaid effects corresponding clockwise motion of the in-bent end 5201 of the customary idling-speed stop lever 52 (FIG. 4) affixed to the end of the throttle butterfly shaft 42 opposite that which carries the throttle lever 44, away from the stop end of a so-called idling adjustment screw 54 which, by reference to FIG. 4, is threaded through a fixed projection 26a on the carburetor 26, in position such that its stop end is accessible to said in-bent end 52a. It is a feature of the invention that this clockwise motion of the throttle stop lever 52 is stopped by engagement of its said in bent end 52a against the head of an adjustable-position stop screw 56 whose shank end is threaded into a stop arm 57 andsecured in adjusted position by a lock nut 58, said stop arm 57 being secured between carburetor attachment flange 26 and carburetor mounting nut 59. Thus, the respective positions of the idling adjustment screw 54 and the stop screw 56 determine the extent of angular motion in either direction that can be imparted to the throttle butterfly shaft 42.

By design, when the toggle lever assembly 40, the throttle lever 42, and the throttle stop lever 52 are in their respective full-line positions in which they are shown in FIGS. 3 and 4, which are determined by engagement of the'in-bent end 52a of the throttle stop lever against the end of the idling adjustment screw 54, the throttle-valve shaft 42 is in an angular position in which the throttle butterfly mounted thereon supplies the fuel-air mixture required to run the engine 20 at idling speed; and when said parts are in their broken-line positions shown in FIGS. 3 and 4, as established by engagement of said end 52a of the stop lever against the head of the stop screw which sets the throttle butterfly in its full-open position, which sets the throttle butterfly in its full-open posiion, i.e. that position in which the butterfly will supply the proper fuel-air mixture required to run said engine at the high speed determined to be its proper operating speed for the particular tamper which it drives.

In practice, the idling adjustment screw 54 will be adjused at the factory to a position establishing a throttleopen setting for an engine speed determined to be the proper idling or warm-up speed for the engine 20, for example, a speed of 1,300 to 1,400 r.p.m.; and similarly the stop screw 56 will be factory adjusted to a position establishing a throttle-open setting producing an engine operating speed determined to be the proper speed for most effective tamping without excessive vibrations being engendered, i.e. a speed of approximately 3,100 rpm.

In addition to the advantage of a speed-regulating means as just described in pre-setting the carburetor throttle to produce the proper idling and operating speeds at which the tamper is to operate in the field, said regulating means provides yet another advantage, namely, that the toggle spring 46 forming a component of said means always functions to impose suflicient pressure on the throttle butterfly shaft 42 in both of its idling and high speed settings as to maintain the shaft in relatively fixed position, thereby substantially reducing Wear on said shaft due to vibration.

Even with tampers equipped with engine-speed regulating means according to the invention it is still not possible for the operator in the field to determine if his tamper is running at its rated proper speed without the use of some instrument such as a vibrometer or tachometer. Accordingly, to correct the situation of tamperengine speed being in question, the invention provides built-in means enabling said operator to visually determine if a tamper is operating on speed according to the manufacturers specifications. Preferably, said means makes use of the governor mechanism and its lever with which tamper engines are conventionally provided by the manufacturer thereof, although not as a means for effecting carburetor throttle butterfly regulation as heretofore. Accordingly, if the engine as supplied to the tamper manufacturer incorporates control linkage between the governor lever and the carburetor, such is removed as are the manual throttle lever and any linkage between it and the governor lever, which latter is retained. More particularly, referring now to FIG. 2, such generally illustrates a conventional governor lever, herein designated 60, positioned on the operator side of the engine crankcase cover 62 and generally beneath the aforesaid exhaust muffler 30, and further shows that said governor lever is secured as usual by a clamp 64 to the fulcrum shaft 66 turnable by the governor assembly (not shown) which projects through said cover, whereby it (said lever) is adapted to be bodily turned with the fulcrum shaft in angular amounts proportional to engine crankshaft speeds.

According to the invention, there is provided a biasing spring 68 having its one ,end hooked to the upper end of the governor lever and its other end secured to a tension screw 70 passed through a fixed-position anchor bolt 72 which illustratively is secured to the aforementioned belt-guard housing 22, the spring thus imposing a counterclockwise bias on said governor lever. Lock nuts 74a, 74b on the tension screw disposed to opposite sides of said anchor bolt 72 serve to lock said screw in a desired position of adjustment with respect to the anchor bolt and thus determine the tension or bias imposed on the governor lever by the spring.

The lower end of said governor lever 60 is inscribed with a generally vertical indicating line 76 and a similar but fixed indicating line 78 is inscribed on the engine crankcase cover generally as shown in FIG. 2, i.e. at a location thereof beneath the path of motion of said lever. After the engine has been set at the factory to run at the desired operating speed under full load by means of the previous described high-speed setting or regulating means, enough tension is applied to the spring 63 by means of tension screw 70 and its lock nuts as to move the lower end of the governor lever 60' (then disposed to the left of the fixed indicating line 78 on the crankcase cover) to the right by an amount bringing its indicating line 76 into coincidence with said fixed indicating line.

The coincidence or lack of coincidence of indicating line 76 with the fixed indicating line 78 thereafter serves as a reference to the tamper operator in the field to determine if its engine is running at the proper operating speed. Thus, if the movable indicating line 76 on the governor lever is disposed to the left of the fixed indicating line 78 on the crankcase cover, such indicates that the engine is running too fast. Conversely, if the movable indicating line on the governor lever has swung to the right of the fixed indicating line, such gives indication that the engine is running too slow. In either case, the engine speed should be corrected only by the high-speed carburetor adjustment means provided by the high-speed stop screw 56, in direction and amount as to cause the index or indicating lines 76, 78 to coincide. Allowable limits of non-coincidence of the aforesaid lines will of course be proscribed; for example, up to deviation of the indicating line 76 to the right or left of the fixed indicating line 7 8. In explanation of the governor-lever indicating line 76 being shown as far to the right of the fixed index line 78 in FIG. 2, it is normal for the movable indicating line to swing to the farright when the engine is either idling or stopped.

Thus, in addition to the invention providing engine speed regulating means which establishes but two engine speeds,'namely, idling and proper operating speeds for 7 most eflicient tamping as determined at the factory, the invention further provides built-in continuous, visual 0 speed verification means enabling the tamper operator in the field (or his supervisor) to determine if the engine is running at the proper operating speed and to take suitable speed corrective measures according to the tamper manufacturers instructions if it is not.

While engine speed regulating means according to the invention may of course be applied to the carburetor of any engine so functioning that only two (low and high) speed settings are required or desired, the interdependence of such form or means of engine speed regulating means and engine speed verification means as herein proposed will be obvious when it is considered that the feasibility of the latter means depends substantially on the use of an engine carburetor having only two settings, one being a high-speed setting and the other a low or idling speed setting, as provided by the speed-regulating means of the invention.

Without further analysis, it will be appreciated that engine speed regulation and visual speed verification means constructed and operating as described and illustrated in the foregoing achieves the desirable objectives of the invention in simple yet fully effective and practical manner. However, as many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. Vibratory-type soil and aggregate compacting apparatus of the character described including a vibratory mechanism, a prime mover therefor, and manually controlled, toggle-actuated means carried by said prime mover for so adjusting the speed thereof that it will run at only a fixed low idling speed or a fixed high speed determined to be the proper operating speed for the apparatus, and means also carried by said prime mover providing a visual indication of any deviation of actual prime mover speed from said proper operating speed as enables an operator to verify that the apparatus is being operated at the proper operating speed.

2. Apparatus according to claim l, wherein said prime mover comprises a gas engine mounting a carburetor including a throttle valve mounted on a rotary throttle shaft, and wherein said toggle-actuated means is effective through said throttle shaft to set said throttle valve in but either one of two open positions, one setting being that producing said idling speed and the other setting being that producing said operating speed.

3. Apparatus according to claim 2 wherein said toggleact-uated means includes a manually controlled toggle lever having one end pivotally mounted for turning movement about the axis of said throttle shaft between first fixed stop means, a throttle lever having one end fixed to said throttle shaft and being movable between two angular positions, one of which establishes idling speed and the other establishes proper operating speed of said englue, and a toggle spring interconnecting the other ends of said levers and being operative responsive to manual movement applied to said toggle lever to impart movement to said throttle lever and thereby to said throttle shaft between said two positions, and second stop means operative to determine the stop positions of said throttle lever shaft.

4. Apparatus according to claim 3, wherein said toggle spring is operative to impose sufiicient bias on said shaft in both of its angular positions as to prevent vibration thereof and thereby substantially reduce wear on said shaft due to vibration.

5. Apparatus according to claim 3, wherein said speed adjusting means further includes means for adjusting the high speed setting of the throttle valve.

6. Apparatus according to claim 3, wherein said speed adjusting means further includes means for adjusting both the idling and the low speed settings of the throttle valve.

7. Apparatus according to claim 1, wherein said speed verification means comprises speed governor mechanism including a generally upright governor lever disposed externally of said prime mover and mounted thereon for swinging motion to opposite sides of a vertical in accordance with the speed of said prime mover, said vertical being defined by a fixed vertical line inscribed on an outer surface of said prime mover over which said lever moves, said lever being also inscribed with a longitudinal line, and means for causing motion of the lever in a manner in which its vertical line coincides with said fixed vertical line when said prime mover is operating at said fixed high speed.

8. Apparatus according to claim 2, wherein said speed verification means comprises speed governor mechanism driven from the crankshaft of said gas engine and including a generally upright governor lever disposed externally of the crankcase cover and being mounted for swinging motion to opposite sides of a vertical in accordance with the speed of the engine crankshaft; said vertical being defined by a fixed vertical line inscribed on said crankcase cover, said lever having a longitudinal line inscribed thereon, and means for modifying the normal action of the lever in accordance with crankshaft speed in such manner that the line of the lever will coincide with said fixed line on the crankcase cover only when the engine is running at said proper operating speed.

9. Apparatus according to claim 8, wherein said lever swings about an axis disposed intermediate its ends and its line is inscribed on the lower end thereof, and wherein said lever-action modifying means comprises adjustable lever-biasing means extending between the upper end of said lever and a fixed point on the engine.

10. In vibratory-type soil and aggregate compacting apparatus including a vibratory mechanism powered by a gasoline engine having a carburetor for supplying a fuel-air mixture to said engine in accordance with the setting of a throttle butterfly valve mounted on a rotary shaft, the improvement comprising means carried by said carburetor for so adjusting the speed of the engine that it will run at only a fixed low idling speed or at a higher speed determined to be the proper operating speed for the apparatus, said means comprising a manually-settable two-position toggle mechanism mounted on said carburetor and operatively connected to said shaft and adapted to actuate said shaft between two fixed positions, one of which determines engine idling speed and the other determines proper engine operating speed, and stop means also carried by said carburetor for establishing said two fixed positions of said shaft.

11. The improvement according to claim 10, wherein said stop means are each manually adjustable so as to effect adjustment of said two fixed positions.

12. In vibratory-type soil and aggregate compacting apparatus including a vibratory mechanism powered by a gasoline engine having a carburetor for supplying a fuelair mixture to said engine in accordance with the setting of a throttle butterfly valve mounted on a rotary shaft, the improvement comprising means carried by said carburetor for so adjusting the speed of the engine that it will run at only a fixed low idling speed or at a higher speed determined to be the proper operating speed for the apparatus, said means comprising a manually controlled throttle-lever assembly having one end pivotally mounted on said shaft for arcuate movement about the axis thereof in opposite directions between a first pair of stop means, a throttle shaft lever having one end afiixed to the throttle butterfly shaft, and a torsion-type toggle spring linking the other ends of said throttle lever assembly and throttle shaft lever and being operative responsive to its over center movement to effect movement of said throttle shaft lever and thereby of said shaft between positions determined by a second pair of stop means, one of said positions determining engine idling speed and the other position determining proper engine operating speed.

butterfly throttle shaft may move.

References Cited UNITED STATES PATENTS Johnson et a1. 123-98 10 McMillan.

Altemose 123-98 XR Shephar-d et a1. 123-98 XR Brown 94-48 Frohnauer 94-48 JACOB L. NACKENOFF, Primary Examiner. 

